This invention relates generally to resins for hairdressings and more particularly to water-soluble ampho-ionic resins which exhibit excellent effectiveness as hairdressings.
The resins for hairdressings according to this invention are particularly suitable for use in the form of aerosols.
The practice of fixing or setting hair on human heads with resins thereby to impart a desired headdress shape thereto is known. For facility in removal by shampooing, hairdressing resins should be water soluble.
As such hairdressing resins, nonionic, anionic, and cationic resins have heretofore been used. Such resins known in the prior art, however, cannot be said to be fully satisfactory in all cases.
More specifically, polyvinyl methyl ether and polyvinyl pyrrolidone are well known examples of nonionic resins. Polyvinyl pyrrolidone resins are easily affected by humidity conditions, and films thereof prior to absorption of moisture are hard and are readily subject to a flaking phenomenon. On the other hand, these resins become extremely soft under high-temperature high-humidity condition and give rise to a blocking phenomenon. As a consequence, when these resins are applied under these conditions to the head, the hair filaments stick to each other, whereby combing or brushing becomes difficult or may become impossible. These effects due to humidity are even more pronounced in the case of polyvinyl methyl ether resins.
As anionic resins, copolymers resins having a vinyl carboxylic acid such as, for example, acrylic acid or methacrylic acid, as an ionic radical are known and are at present the most widely used resins for hairdressing. These anionic resins are not readily affected by humidity and exhibit better properties than nonionic resins but, because they are anionic, have weak affinity with respect to hair. On one hand, films of these resins must be hard for increased hairdressing effectiveness, but this increases the possibility of flaking phenomenon. Furthermore, because these resins are anionic, the addition thereto of cationic substances is limited, and there is the possibility of caking phenomenon due to agents such as a rinsing agent at the time of shampooing.
Cationic resins have greater affinity than nonionic and anionic resins with respect to hair but, similarly as in the case of nonionic resins, are readily affected by humidity. Furthermore, because these resins are cationic, there is the risk of their being toxic or epispastic. The addition to these resins of anionic substances is also limited, and there is the problem of caking phenomenon due to the shampoo (anionic) during shampooing.
That excellent resin compositions for hairdressing (for fixing or setting hair in place) are obtained by using resins having an ampho-ionic property has previously been disclosed by us in Japanese Patent Laid Open Publication No. 9732/1976. In this case, however, during the ampho-ionization of the copolymer, precipitation occurs in some instances at the time of modification when a sodium salt or a potassium salt of halo-acetic acid is used, and, because of the resulting precipitate, the properties of the film are not always good. Furthermore, in the case where the preparation is used in the form of an aerosol, the container vessel tends to be readily corroded.